Whats the best way to mask or extract parts of an image using an RGB pass in nuke?
I’ve been using shuffle copy to put a single color channel into a new alpha then using the rotopoint node to mask. Im sure this is quite cumbersome and not the proper way to do things. What’s the best solution?
Trying my first project in nuke after switching from AE and this is driving me mad. Is there no simple “mask” node?
most of the nodes have a seperate mask input, you could/should connect the RGB mask image to that and set in the “effect” node the proper mask channel. for most of the stuff it will be good this way and there is no need to seperate elements, do effects on it and merge them back again
but if you really need to seperate an element by its mask, i would use a copy or shuffle copy to copy the mask into the alpha and use a premult afterwards. you can also build this as a macro or download it already here
If I understand correctly you want to punch a hole in your image using an rgb pass.
I attached a quick screen down showing you that im using 3 node SHUFFLE, COPY, PREMULT to do this. Taking the RED channel (which are the front circular materials of the goggle) and adding them as alphas and then PREMULT them to have the alpha to be effective. BUT it will do the reverse if you do not check the INVERT option in PREMULT.
Thank you for both replies, this is exactly what I needed! I wouldn’t normally need to separate the elements just to add them back together, it’s just a special case for this project I’m doing; however I had no idea how to achieve this in an economic way, and both comments are very helpful to me
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